The present invention generally relates to surgery on body tissues and organs. More specifically, the present invention relates to apparatus for engaging body tissue during surgery to position an organ or immobilize tissue subject to motion, such as the heart wall.
Coronary artery disease remains the leading cause of morbidity and mortality in Western societies. A number of approaches have been developed for treating coronary artery disease. In less severe cases, it is often sufficient to merely treat the symptoms with pharmaceuticals or to treat the underlying causes of the disease with lifestyle modification. In more severe cases, the coronary blockage can be treated endovascularly using techniques such as balloon angioplasty, atherectomy, laser ablation, stents, and the like. In cases where these approaches have failed or are likely to fail, it is often necessary to perform a coronary artery bypass graft procedure.
The coronary artery bypass graft procedure traditionally required a heart-lung or cardiopulmonary bypass. Due to the risks incurred during cardiopulmonary bypass, beating heart bypass surgery techniques have been developed to allow coronary artery bypass without cardiopulmonary bypass. Several systems are presently available which attempt to immobilize epicardial tissue in the immediate vicinity of an anastomosis site through a pressure stabilizer employing a simple mechanical fork. Such a device stabilizes the heart by pressing a fork downwards onto the heart surface. The fork is typically mounted to an elongated shaft, which in turn is typically mounted to a retractor, holding the patient""s ribs apart to create an operative window. Angular movement of the shaft relative to the retractor in some cases is accomplished by means of a turret, which may be clamped in its desired rotational position. Longitudinal movement of the shaft relative to the retractor is typically allowed as well, and clamping mechanisms are typically provided to allow clamping of the shaft to the turret and locking of the fork relative to the shaft. Exemplary pressure stabilization devices are disclosed in U.S. Pat. No. 5,876,332, issued to Looney and U.S. Pat. No. 6,036,641, issued to Taylor, et al., both incorporated herein by reference in their entireties.
Suction stabilization systems, such as the Medtronic Octopus(copyright) Tissue Stabilizer (available from Medtronic, Inc., Minneapolis, Minn. USA), instead employ a comparatively long, flexible arm carrying a pair of suction paddles or pods at its distal end. During use, the arm is typically secured to a surgical spreader or retractor, holding the patient""s ribs apart to create an operative window. The pods are placed on either side of the anastomosis site and suction is applied to grip and immobilize the surface of the heart. Thereafter, tension is applied along the length of the arm to lock the arm in its position and to lock the position of the pods relative to the arm. Medtronic""s device is generally disclosed in pending U.S. patent application Ser. No. 09/396,047, filed by Boone, et al. on Sep. 15, 1999, for a xe2x80x9cMethod And Apparatus For Temporarily Immobilizing A Local Area Of Tissue, incorporated herein by reference in its entirety. In this device, a single knob, mounted to the proximal end of the arm, is employed to lock the arm in position and additionally to spread the pods somewhat, slightly stretching the heart""s surface to provide additional stabilization of the heart surface. In such devices, adjustment of the shaft relative to the surgical retractor is accomplished by varying the configuration of the flexible shaft, prior to locking it in its desired position. Other examples of suction stabilization devices are disclosed in U.S. Pat. No. 6,113,534, issued to Koros, et al., U.S. Pat. No. 6,007,486, issued to Hunt, et al, U.S. Pat. No. 5,836,311, issued to Borst, et al. and U.S. Pat. No. 5,727,569, issued to Benetti, et al., all incorporated herein by reference in their entireties.
In conjunction with stabilization devices, suction retractors are often employed to position the heart to allow access to the desired anastomosis site. The Medtronic Starfish(trademark) device and the Guidant Axius(trademark) Expose(trademark) device are examples of commercially available suction retractors. These devices employ a single, larger suction pod to engage the heart, typically in the vicinity of the heart apex. The suction pod is carried by a flexible arm, which, like the suction stabilizers discussed above, also may be locked into a desired configuration by tension applied along their length. The application of tension to the arm may also serve to lock a carrier for the suction pod relative to the arm to fix the suction pod in a desired orientation relative to the arm, as in the Guidant device. The Medtronic device is described in pending U.S. patent application Ser. No. 09/679,294, filed Jun. 12, 2001 by Keogh, et al. for a xe2x80x9cMethod and System for Organ Positioning and Stabilization, incorporated herein by reference in its entirety. The Guidant device is described in the brochure xe2x80x9cAxius(trademark) Expose(trademark) Device, Instructions for Use, Guidant Corp., 2001, P/N 30462, Rev. A, also incorporated herein by reference in its entirety. Other suction retractors are described in U.S. Pat. No. 6,019,772, issued to Spence, et al. and PCT Publication No. WO 01/17437 by Peng, both also incorporated herein by reference in their entireties.
The present invention provides an improved stabilizer or retractor, which includes features intended to allow for easier use. These devices are of the type having an elongated arm, hereafter referred to as the distal arm, carrying a tissue-contacting mechanism at its distal end. In preferred embodiments, the devices include a base for mounting the device to a surgical spreader or retractor, carrying a turret coupled to proximal end of the distal arm and allowing rotation of the distal arm relative to the base. The devices in these embodiments also comprise a tensioning mechanism for locking the turret and/or other functional components of the devices in a desired position or configuration. The tensioning mechanism in turn is mounted to the turret or other structure attaching the distal arm to the base by means of a shorter, proximally extending flexible arm, hereafter referred to as the proximal arm.
The tensioning mechanism typically includes a knob, handle or control mechanism of fairly substantial size. The flexible proximal arm allows the tensioning mechanism to be moved relative to the base so that it can be placed more conveniently in the operative field. The inclusion of the proximal arm is believed especially desirable in the context of a device having a turret for positioning the distal arm, as absent this feature, rotation of the turret may sometimes place the distal arm in a desired position at the cost of placement of the tensioning mechanism in an undesirable location. The flexible proximal arm allows the tensioning mechanism to be moved to a more desirable location.
In preferred embodiments, the stabilizer takes the form of a suction stabilizer or retractor having a suction pod or pods mounted to the distal end of a flexible distal arm. In these embodiments, the distal arm is locked into a desired position and configuration by means of the tensioning mechanism. While the invention is most preferably embodied in a suction stabilizer or retractor with a flexible distal arm, certain aspects of the invention may be useful in the context of a pressure stabilizer and/or a stabilizer or retractor with a rigid distal arm.